A convertible automobile comprises an open vehicle body that mounts an articulated frame or top stack, that is movable by manual or power means between a folded lowered or stored position, which opens the passenger compartment, and an unfolded raised position, which covers the passenger compartment. In lowered position, most convertible tops occupy a storage compartment rearwardly of the passenger compartment known as the storage well or boot. The top stack usually comprises a header, that engages the vehicle windshield header in raised position, a rear bow that seals against the vehicle body, and a plurality of intermediate bows.
A fabric cover is secured to the top header and to the rear bow of the top stack or to the body around the periphery of the storage well. The cover includes a rear opening that mounts a glass or plastic backlight. The cover usually is secured to the intermediate bows to prevent ballooning of the top, which otherwise would occur due to the pressure differential between the inside and outside of the vehicle caused by the aerodynamics of the vehicle at speed.
The cover is configured to seal against the vehicle side windows when both are raised. Combined with its attachment to the header and rear rail, this forms a seal between the top periphery and the vehicle body to prevent the ingress of rain and wind to the passenger compartment. It also provides some security against unauthorized vehicle entrance, unless, of course, the top fabric is cut.
In some convertible tops, such as is shown in U.S. Pat. No. 4,741,571 to Godette, the rear bow is movable away from the body during top raising and lowering to enable movement of a hard boot cover beneath the rear bow to cover the boot in both top raised and lowered positions. To accommodate this movement, the top fabric is secured to the rear bow.
More conventionally, the rear of the top fabric is secured directly to the body and the boot is open to the passenger compartment when the top is raised. When the top is lowered, the boot may is conventionally covered by attachment of a separate soft or hard cover to the vehicle body around the periphery of the boot.
Trimming of the top, or attachment of the fabric cover to the frame and to the vehicle, is a tedious and exacting process. The fabric cover is conventionally secured to the top header by stapling or nailing the fabric to a plastic tack strip carried by the header. Similarly, covers that are secured to the rear bow are nailed to a tack strip carried by the rear bow.
In those vehicles where the fabric cover is attached directly to the body, the fabric is tacked to a similar tack strip or clamped to the body by a clamping strip that is screwed into the body at closely spaced intervals near the vehicle belt line.
The fabric cover carries sewn-in lateral material loops adjacent the intermediate bows which receive metal lister bars that are attached to the bows. This keeps the fabric cover closely secured to the frame to prevent ballooning during vehicle operation.
In these arrangements, it requires skill to assure that the tacking and/or clamping is done accurately, or the fabric cover will not have a smooth fitted appearance, free of such defects as wrinkles or bulges. If such defects do occur, reworking of the top requires prying the tacks off and retacking of the fabric cover. Much hand fitting on a cut-and-try basis is normally required to assure a good fit of the material to the top frame and to the vehicle body.
Another drawback to this technique is that the tacking process violates the integrity of the fabric by weakening it. Reworking puts more holes in the fabric, further weakening it.
Convertible top covers, being fabric, have a finite life significantly shorter than that of the vehicle. Thus, one or more replacement tops may need to be installed during a convertible vehicle's life. This top replacement process is more laborious than the original installation, since it requires tearing out the old top cover and installing the new cover in the same manner as the original installation.
Attempts have been made to simplify the top installation and reinstallation process. U.S. Pat. No. 2,954,999 to Fingerman et al discloses a process in which the rear fabric edge is attached to a trim strip which is then screwed to the periphery of the boot.
U.S. Pat. No. 3,090,646 to Johnson relates a method of sewing the rear fabric edge of the cover to a retainer cord which is inserted in a groove in a movable rear bow and retained there by an adjacent rubber weatherstrip and a clamping trim strip. However, this arrangement presupposes that the fabric cover is dimensioned correctly, which is often not the case.
U.S. Pat. No. 3,237,983 relates a method for attaching the fabric cover to the top header which involves inserting a plurality of nails through the cover fabric into preformed slots.
Although the above top attaching methods present some improvement, they still do not assure a quality fit of the fabric cover to the vehicle body and top frame and are inefficient in requiring too much skilled labor.
It would be desirable to provide a system of convertible top trimming that is much simpler and quicker than current trimming methods and facilitates the correction of installation errors. It would also be desirable to provide such a system that requires a much lesser skill level of top installation personnel than is now required to trim convertible tops, either originally or replacement.